3-Heterothio derivatives of (α-thiocarbonylamino) cephalosporins

ABSTRACT

3-Heterothio( alpha -thiocarbonylamino)cephalosporin derivatives of the general formula   &lt;IMAGE&gt;     wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion or the group   &lt;IMAGE&gt;    R1 is hydrogen, lower alkyl, cyclo-lower alkyl, unsaturated cyclo-lower alkyl, phenyl, substituted phenyl or thienyl; R2 and R5 each is hydrogen or lower alkyl; R3 is a five or six membered nitrogen, sulfur and/or oxygen containing ring system; and R4 is lower alkyl, phenyl or phenyl-lower alkyl; are useful as antibacterial agents.

SUMMARY OF THE INVENTION

This invention relates to new3-heterothio-(α-thiocarbonylamino)cephalosporin derivatives of theformula ##STR3##

R represents hydrogen, lower alkyl, phenyl-lower alkyl, tri(loweralkyl)silyl, trihaloethyl, a salt forming ion or the group ##STR4## R₁represents hydrogen, lower alkyl, cyclo-lower alkyl, unsaturatedcyclo-lower alkyl, phenyl, substituted phenyl wherein the phenylsubstituents are lower alkyl, lower alkoxy, hydroxy, halogen, amino,ureido or methylsulfonylamino, or thienyl; R₂ and R₅ each representshydrogen or lower alkyl; R₃ represents a five or six-memberedheterocycle including thiadiazole, oxadiazole, triazole, thiatriazole,tetrazole and their lower alkyl (R₆) substituted analogs; R₄ representslower alkyl, phenyl or phenyl-lower alkyl.

The preferred members within each group are as follows: R is hydrogen,alkali metal, diphenylmethyl or ##STR5## especially hydrogen,pivaloyloxymethyl, sodium or potassium; R₁ is hydrogen, phenyl orthienyl, especially phenyl or thienyl; R₂ is hydrogen or methyl; R₃ ispreferably (lower alkyl)tetrazole or (lower alkyl)thiadiazole,especially wherein the lower alkyl group is methyl; R₄ is methyl ort-butyl.

DETAILED DESCRIPTION OF THE INVENTION

The various groups represented by the symbols have the meanings definedbelow and these definitions are retained throughout this specification.

The lower alkyl groups are the straight and branched chain hydrocarbongroups in the series from methyl to heptyl, the C₁ to C₄ members andespecially methyl and ethyl being preferred. The lower alkoxy groups areof the same kind.

The phenyl-lower alkyl radicals include a phenyl ring attached to alower alkyl group of the kind described above as well as thosecontaining two phenyl groups such as diphenylmethyl.

The salt forming ions represented by R are metal ions, e.g., alkalimetal ions such as sodium or potassium, alkaline earth metal ions suchas calcium or magnesium, or an amine salt ion, e.g., a (loweralkyl)amine like methylamine or triethylamine or a cyclo-loweralkylamine, like dicyclohexylamine, etc.

The halogens are the four common halogens, of which chlorine and bromineare preferred. In the case of trihaloethyl group represented by R,2,2,2-trichloroethyl is preferred.

R₃ is thiadiazole, oxadiazole, triazole, thiatriazole, tetrazole and thelower alkyl substituted analogs of each of these except thiatriazole,especially 1,3,4-thiadiazole, 1,2,4-thiadiazole, tetrazole,5-methyl-1,3,4-thiadiazol-2-yl, 3-methyl-1,2,4-thiadiazol-5-yl and1-methyl-tetrazol-5-yl. The heterocyclics have, in particular, thesestructures: ##STR6## wherein R₆ is hydrogen or lower alkyl, especiallymethyl.

The new cephalosporin derivatives of this invention are produced byseveral methods. According to one method, a 7-aminocephalosporanic acid(7-ACA) derivative of the formula ##STR7## is reacted with an acid ofthe formula ##STR8## or an activated derivative like an activated esteror mixed anhydride, or in the presence of a coupling agent likedicyclohexylcarbodiimide.

One preferred synthesis comprises reacting the acid of formula III withthe diphenylmethyl ester of the 7-ACA derivative of formula II and thenhydrolyzing the ester with trifluoroacetic acid and anisole to obtainthe free carboxyl group in the 4-position.

The reaction between the 7-aminocephalosporanic acid compound and theacid of formula III can be carried out, for example, by dissolving orsuspending the acid in an inert organic solvent such as chloroform,tetrahydrofuran, methylene chloride, dioxane, benzene or the like, andadding, at a reduced temperature of about 0°-5° C, about an equimolaramount of the 7-ACA compound in the presence of an activating compoundsuch as dicyclohexylcarbodiimide. The product of the reaction is thenisolated by conventional procedures, e.g., by concentration orevaporation of the solvent. If a derivative of the7-aminocephalosporanic acid compound, such as the diphenylmethyl esteris used, the free acid is obtained by hydrolysis, e.g., withtrifluoroacetic acid or the like. Salts can then be derived from thefree acid.

According to another embodiment, an acid of formula III is reacted witha compound of the formula ##STR9## preferably wherein R isdiphenylmethyl. When R is the preferred diphenylmethyl group, it isconverted to the free acid with trifluoroacetic acid and anisole. Theproduct of the formula ##STR10## is then reacted with a thiol of theformula

    R.sub.3 --SH

in basic solution, e.g., at a pH of about 7.8, to obtain the product offormula I.

According to still another embodiment, a compound of the formula##STR11## is made to react with a compound of the formula ##STR12##wherein Y is an activating group like-O-lower alkyl, halogen or --S--CH₂--COOH, in a solvent like methylene chloride in the presence oftriethylamine, then adding a source of hydrogen ion like hydrogensulfide.

When R is the acyloxymethyl group ##STR13## this group can be introducedinto the 7-aminocephalosporanic acid moiety prior to the reaction withthe acid of formula III or the activated derivative by treatment withone to two moles of a halomethyl ester of the formula ##STR14## whereinhal is halogen, preferably chlorine or bromine, in an inert organicsolvent such as dimethylformamide, acetone, dioxane, benzene or thelike, at about ambient temperature or below.

The acid of formula III is produced by reacting an ester, preferably thediphenylmethyl ester of an α-amino acid of the formula ##STR15## with athioformate ##STR16## (wherein Y is lower alkyl) in an inert solventlike tetrahydrofuran at about ambient temperature and adding a source ofhydrogen ion, e.g., hydrogen sulfide and finally treating withtrifluoroacetic acid and anisole.

Further process details are also provided in the illustrative examples.

Certain of the compounds of this invention may exist in differentoptically active forms. The various stereoisomeric forms as well as theracemic mixtures are within the scope of the invention.

The compounds of this invention have a broad spectrum of antibacterialactivity against both gram positive and gram negative organisms such asStaphylococcus aureus, Salmonella schottmuelleri, Pseudomonasaeruginosa, Proteus vulgaris, Escherichia coli and Streptococcuspyogenes. They are useful as antibacterial agents, e.g., to combatinfections due to organisms such as those named above, and in generalthey can be utilized in a manner similar to cephradine and othercephalosporins. For example, a compound of formula I or aphysiologically acceptable salt thereof can be used in various animalspecies affected by infections of such bacterial origin in an amount ofabout 1 to 75 mg/kg daily, orally or parenterally, in single or two tofour divided doses.

Up to about 500 mg. of a compound of formula I or a physiologicallyacceptable salt thereof is administered by incorporating in an oraldosage form such as tablets, capsules or elixirs or in an injectableform in a sterile aqueous vehicle prepared according to conventionalpharmaceutical practice.

The following examples are illustrative of the invention. Alltemperatures are in degrees celsius. Additional variations are producedin the same manner by appropriate substitution in the starting material.

EXAMPLE 13-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

A mixture of 13.6 g. (0.05 M) of 7-aminocephalosporanic acid (7-ACA) in100 ml. of water and 50 ml. of acetone are brought to pH 8 with sodiumhydroxide while stirring. 7.5 g. (0.057 M) of2-methyl-1,3,4-thiadiazole-5-thiol are added and the mixture is heatedat 80° for four hours. After cooling to 5°, this is acidified to pH 3.5with dilute hydrochloric acid and stirred for 15 minutes. Theprecipitated solid is filtered under suction and washed with acetone.This3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid is purified by dissolving in sodium bicarbonate solution andreprecipitating with 2N hydrochloric acid; yield 12.7 g., m.p. 206°.

EXAMPLE 23-[[(3-Methyl-1,2,4-thiadiazol-5-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

By substituting 3-methyl-1,2,4-thiadiazole-5-thiol for the2-methyl-1,3,4-thiadiazole-5-thiol in the procedure of Example 1, 11.6g. of3-[[(3-methyl-1,2,4-thiadiazol-5-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, m.p. 186° (dec.) are obtained.

EXAMPLE 33-[[(1-Methyl-1H-tetrazol-5-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

By substituting 0.057 M of 1-methyl-1H-tetrazole-5-thiol for the2-methyl-1,3,4-thiadiazole-5-thiol in the procedure of Example 1,3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid is obtained.

EXAMPLE 47-Amino-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester

18 g. of7-amino-3-[[(5-methyl-1,3,4-thiadiazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid are suspended in 350 ml. of tetrahydrofuran. 4.1 ml. of 70%perchloric acid are added dropwise. After 30 minutes, a slightly turbidsolution forms. This solution is filtered and to the filtrate is addeddropwise with stirring 12 g. of diphenyldiazomethane and 20 ml. oftetrahydrofuran. After 3 hours, the reaction mixture is poured into 2liters of absolute ether. The solid, light brown precipitate, which isthe perchloric acid salt of the desired product, is dried over Kieselgelin a desiccator. To obtain the base, the perchloric acid salt isdissolved in water and treated with the calculated equivalent ofpotassium bicarbonate. The aqueous solution obtained is extracted withchloroform. The chloroform phase is treated with activated carbon andsodium sulfate to obtain the 10 g. of the product,7-amino-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,diphenylmethyl ester, as a light brown powder, m.p. 157°-159°. Theproduct is recrystallized from tetrahydrofuran/petroleum ether.

7-Amino-3-[[(3-methyl-1,2,4-thiadiazol-5-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester is similarly obtained by substituting theproduct of Example 2.

EXAMPLE 5

7-Amino-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester

The product,7-amino-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-enecarboxylicacid, diphenylmethyl ester, m.p. 168°-169° (dec.), is obtained by theprocedure of Example 4 utilizing as starting material7-amino-3-[[(1-methyl-1H-tetrazol-5-yl)-thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid.

EXAMPLE 63-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-7β-[[phenyl[(thioxomethyl)amino]acetyl]amino]-5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylicacid and sodium salt

a.7β-[[[[[(4-methoxyphenyl)methoxy]carbonyl]amino]phenyl-acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester

3.78 g. (0.012 mol.) of[[[(4-methoxyphenyl)methoxy]-carbonyl]amino]benzeneacetic acid (preparedas described in U.S. Pat. No. 3,560,489, Feb. 2, 1971) are dissolved in100 ml. of tetrahydrofuran and added to a solution of 4.95 g. (0.01mol.) of7-amino-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester in 50 ml. of methylene chloride. The mixtureis cooled to 0°-5° and at this temperature a solution of 2.27 g. (0.011mol.) of dicyclohexylcarbodiimide is added dropwise. The mixture isstirred for 90 minutes at 0°-5° and 90 minutes at room temperature. Theprecipitated dicyclohexylurea (2.4 g.) is filtered off. The filtrate isconcentrated and the residue is taken up in a mixture of ethyl acetateand tetrahydrofuran (3:1). The organic phase is washed once with sodiumbicarbonate solution and twice with water, then decolorized withactivated carbon, dried with magnesium sulfate, filtered andconcentrated to a small volume. The precipitated product is filteredunder suction. 5.5 g. of7β-[[[[[(4-methoxyphenyl)methoxy]carbonyl]amino]phenylacetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,diphenylmethyl ester, are obtained, m.p. 145°-150° (dec.). Byconcentrating the mother liquor and adding ether, an additional 0.7 g.of product is obtained.

b. 7β-[(aminophenylacetyl)amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylicacid, trifluoroacetate salt

3.7 g. of the product of part a are added at 0°-5° to a mixture of 74ml. trifluoroacetic acid and 22 ml. of anisole. After 10 minutes. thetrifluoroacetic acid is evaporated under vacuum and ether is added tothe residue. 2.6 g. of7β-[(aminophenylacetyl)amino]-3-[[1-methyl-1H-tetrazol-5-yl)thio]]methyl-8-oxo-5-thia-azabicyclo[4.2.0]-oct-2-ene-2-carboxylicacid, trifluoroacetate salt is obtained.

c.3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-7β-[[phenyl[(thioxomethyl)amino]acetyl]amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

1.8 g. of the product of part b are suspended in 31 ml. ofethylthioformate, cooled to 0°-5° and 6.8 ml. of a solution oftriethylamine in methylene chloride (2.5 ml. of triethylamine andsufficient methylene chloride to make 25 ml.) are added. After 15minutes, a stream of hydrogen sulfide is passed in for 15 minutes withstirring. After three hours, petroleum ether is added untilprecipitation is complete, and then the mixture is filtered undersuction. The triethylamine salt of3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-7β-[[phenyl[(thioxomethyl)-amino]acetyl]amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid thus obtained is dissolved in 30 ml. of water, the solution isadjusted to pH 6.5 with sodium bicarbonate, filtered and the filtrate isacidified to pH 1.5 with 2N hydrochloric acid. 0.9 g. of product isobtained, m.p. 158°-160° (dec.).

d.3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-7-β-[[phenyl[(thioxomethyl)amino]acetyl]amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, sodium salt

0.51 g. of3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-7β-[[phenyl[(thioxomethyl)amino]acetyl]amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid from part c are brought into solution with 10 ml. of a 0.1 N sodiumbicarbonate solution and the clear solution is freeze dried. Aquantitative yield of the sodium salt is obtained, m.p. 180°-190°(dec.).

EXAMPLE 77-[D-2-[[(2-thienyl)-2-(thioxomethyl)amino]acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

a. 8.0 g. of magnesium oxide are suspended in 200 ml. of water. 15.7 g.of D-2-(2-thienyl)glycine are added to the suspension followed by asolution of 22.8 g. of p-methoxybenzyloxycarbonylazide in 200 ml.dioxane. The mixture is stirred for 3 days at room temperature.

The reaction mixture is then filtered and the filtrate is extracted oncewith 125 ml. of diethyl ether. The ether layer is then discarded. Theaqueous phase is cooled to 5°-10°, layered with about 150 ml. of ethylacetate and acidifed with 2N hydrochloric acid to pH 2.5. Afterseparating the layers, the aqueous phase is extracted again with 100 ml.of ethyl acetate. The combined ethyl acetate solutions are washed oncewith water, dried over magnesium sulfate and evaporated. The oilyresidue crystallizes on treatment with petroleum ether. The yieldamounts to 30.8 gms. of crude material. After recrystallization fromethyl acetate/petroleum ether, 25.2 gms. ofD-α-[[[(4-methoxyphenyl)methoxy]carbonyl]amino]-2-thiopheneacetic acidare obtained, m.p. 66°-69°. The material is usually contaminated with asmall amount of ethyl acetate which cannot be removed at 35° in vacuum.The material obtained free from ethyl acetate has a melting point89°-92°, [α]_(D) ²⁵ = -62.2 ° (c = 1,tetrahydrofuran)

b.7β-[[[[[(4-methoxyphenyl)methoxy]carbonyl]amino]-(2-thienyl)acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester

The product of part a and7-amino-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene-2-carboxylicacid diphenylmethyl ester are dissolved in 650 ml. of absolutetetrahydrofuran and the solution is cooled to 0°. At this temperature, asolution of 7.3 gms. of dicyclohexylcarbodiimide in 60 ml. of absolutetetrahydrofuran is added dropwise over a period of about 20 minutes. Themixture is stirred at 0° for two hours and an additional two hours atroom temperature. The dicyclohexylurea which precipitates is removed byfiltration. The filtrate is concentrated in vacuum. The residue isdissolved in ethyl acetate, washed with saturated sodium bicarbonatesolution, then with water and dried with magnesium sulfate. Afterfiltration, the filtrate is left overnight in the refrigerator. Thereaction product crystallizes. On filtration 12.2 gms. of7β-[[[[[(4-methoxyphenyl)methoxy]carbonyl]amino]-2-thienyl)acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]-methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,diphenylmethyl ester are obtained, m.p. 126° (dec.). The filtrate isevaporated to dryness. Treatment with ethyl acetate yields a second cropof 2.6 gms. A third crop of 2.6 gms. is obtained when the filtrate isevaporated, dissolved in a small amount of ethyl acetate, precipitatedwith petroleum ether and again treated with ethyl acetate.

c.7-[D-2-amino-2-(2-thienyl)acetamido]-3-[[(1-methyl-1-H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylicacid, trifluoroacetate salt

11.5 gms. of the product of part b are mixed with 30 ml. of anisole,cooled to 0°-5° and 150 ml. of trifluoroacetic acid are added. Thesolution is stirred for 10 minutes at this temperature. Then the solventis stripped off in vacuum and the residue is treated with diethyl ether.8.6 gms. of7-[D-2-amino-2-(2-thienyl)acetamido]-3-[[(1-methyl-1-H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, trifluoroacetate salt are obtained.

d.7-[D-2-[(2-thienyl)-2-(thioxomethyl)amino]acetyl]amino-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

The product of part c is reacted with ethylthioformate in the presenceof triethylamine according to the procedure of Example 6 c to obtain7-[D-2-[[(2-thienyl)-2-(thioxomethyl)amino]acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, m.p. 130° (dec.).

EXAMPLE 87-[DL-2-[[(3-thienyl)-2-(thioxomethyl)amino]acetyl]amino]methyl-[[(1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabycyclo-[4.2.0]oct-2-ene-2-carboxylicacid

7-[DL-2-Amino-2-(3-thienyl)acetamido]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene-2-carboxylicacid, trifluoroacetate salt (prepared by the procedure of Example 7 butsubstituting DL-2-(3-thienyl)glycine for the D-2-(2-thienyl)glycine) isreacted with ethylthioformate according to the procedure of Example 6cto obtain7-[DL-2-[(3-thienyl)-2-(thioxomethyl)amino]acetyl]amino-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid.

EXAMPLE 9 α-[(Thioxomethyl)amino]benzene acetic acid, diphenylmethylester

A solution of 15.9 g. (0.05 mol.) of α-phenylglycine, diphenylmethylester, and 9 g. (0.01 mol.) of ethylthioformate in 50 ml. oftetrahydrofuran is stirred overnight at room temperature. Then a streamof hydrogen sulfide is passed into the solution for ten minutes, thereaction mixture is permitted to stand overnight, then concentrated andpetroleum ether is added to the residue. 16.9 g. ofα-[(thioxomethyl)-amino]benzeneacetic acid, diphenylmethyl ester,crystallizes. The crude product is recrystalized from methanol, m.p.129°-130°.

EXAMPLE 10 α-[(Thioxomethyl)amino]benzeneacetic acid

3.61 g. (0.01 mol.) of α-[(thioxomethyl)amino]-benzeneacetic acid,diphenylmethyl ester are added to a mixture of 30 ml. of trifluoroaceticacid and 5 ml. of anisole at 0°-5° and the mixture is stirred for tenminutes. The mixture is concentrated, sodium bicarbonate solution isadded to the residue and the aqueous phase is extracted with ether. Thisis then layered over with fresh ether, acidified and the aqueous phaseis extracted twice with ether. Concentration of the ether solutionyields α-[(thioxomethyl)amino]benzeneacetic acid as an oily residue.

EXAMPLE 117-[D-2-phenyl-2-[(thioxomethyl)amino]acetyl]amino-3-[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenyl-methyl ester

To a solution of 0.01 mol. of7-amino-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester and 0.012 mol. ofα-[(thioxomethyl)amino]benzeneacetic acid in 100 ml. of tetrahydrofuranis added at 0°-5° a solution of 0.011 mol. of dicyclohexylcarbodiimidein 20 ml. of tetrahydrofuran. The mixture is stirred for 90 minutes at0°-5° and 90 minutes at room temperature, then filtered andconcentrated. The residue is taken up in ethyl acetate, shaken withsodium bicarbonate solution and with water, dried with magnesium sulfateand again concentrated. Petroleum ether is added to the residue and7-[D-2-phenyl-2-[[(thioxomethyl)amino]acetyl]amino]-3-[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, diphenylmethyl ester is obtained as a beige-brown amorphouspowder.

EXAMPLE 127-[D-2-phenyl-2[(thioxomethyl)amino]acetyl]amino-[3-(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl-8-oxo-5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylicacid

2 g. of the product of Example 11 are added to a mixture of 20 ml. oftrifluoroacetic acid and 1 ml. of anisole at 0°-5°, stirred for 10minutes, concentrated and ether is added to the residue.7-[D-2-phenyl-2-[[thioxo-methyl]amino]acetyl]amino-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid is obtained as an amorphous powder.

EXAMPLE 137-[D-2-[(2-thienyl)-2-[(1-thioxoethyl)amino]acetyl]amino]-[(3-methyl-1,2,4-thiadiazol-5-yl)thio]methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

0.01 mol. of7-[D-2-amino-2-(2-thienyl)acetamido]-3-[[(3-methyl-1,2,4-thiadiazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid, trifluoroacetate salt (prepared by the procedure of Example 7, butsubstituting 3-[[(3-methyl-1,2,4-thiadiazol-5-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,diphenylmethyl ester in part b) is brought into solution withtriethylamine in methylene chloride and 0.015 mol. of[(1-thioxoethyl)thio]acetic acid (prepared as described in U.S. Pat. No.3,341,518) is added. The reaction mixture is permitted to stand forthree hours and worked up according to the procedure of Example 7 toobtain7-[D-2-[(2-thienyl)-2-[(1-thioxoethyl)amino]acetyl]amino]-3-[[3-methyl-1,2,4-thiadiazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene-2-carboxylicacid.

EXAMPLES 14 - 38

The products below are obtained by the procedure of Example 7 (Example 6d to obtain the salt) from the α-amino acid ##STR17## and thediphenylmethyl ester of one of the following [produced by the procedureof Examples 1 and 4 (Example 6d to obtain a salt)]:

a.3-[[(5-methyl-1,3,4-thiadiazolyl-2-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid

b. 3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-7-ACA

c. 3-[[(1,3,4-oxadiazol-2-yl)thio]methyl]-7-ACA

d. 3-[[(5-ethyl-1,3,4-oxadiazol-2-yl)thio]methyl]-7-ACA

e. 3-[[(1,2,3,4-tetrazol-5-yl)thio]methyl]-7-ACA

f. 3-[[(1-ethyl-1H-tetrazol-5-yl)thio]methyl]-7-ACA

g. 3-[[(1,2,4-thiadiazol-3-yl)thio]methyl]-7-ACA

h. 3-[[(5-butyl-1,2,4-thiadiazol-3-yl)thio]methyl]-7-ACA

i. 3-[[(3-methyl-1,2,4-oxadiazol-5-yl)thio]methyl]-7-ACA

j. 3-[[(2-methyl-1,3,4-thiadiazol-5-yl)thio]methyl]-7-ACA

k. 3-[[(1,2,4,-thiadiazol-5-yl)thio]methyl]-7-ACA

l. 3-[[(5-methyl-1,2,4-thiadiazol-2-yl)thio]methyl]-7-ACA

m. 3-[[(2-methyl-1H-tetrazol-5-yl)thio]methyl]-7-ACA

n. 3-[[(1,3,4-thiadiazol-2-yl)thio]methyl]-7-ACA

o. 3-[[(1,2,3,4-thiatriazol-5-yl)thio]methyl]-7-ACA

p. 3-[[(1,2,3-triazol-5-yl)thio]methyl]-7-ACA

q. 3-[[(1-methyl-1,2,3-triazol-5-yl)thio]methyl]-7-ACA

    __________________________________________________________________________    Example                                                                       __________________________________________________________________________    14       7-[D-2-phenyl-2-[[(1-thioxoethyl)amino]acetyl]amino]-                         3-[[(1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-                         - 1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.                    15       7-[D-2-phenyl-2-[[(1-thioxobutyl)amino]acetyl]amino]-                         3-[[(1,3,4-oxadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-                        azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.                        16       7-[D-2-[[(1-thioxoethyl)amino]propionyl]amino]-3-                             [[(5-ethyl-1,3,4-oxadiazol-2-yl)thio]methyl]-8-oxo-                           5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                17       7-[D-2-phenyl-2-[[(thioxomethyl)amino]acetyl]amino]-                          3-[[(1,2,4-thiadiazol-5-yl)thio]methyl]-8-oxo-5-thia-                         1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                       18       7-[D-2-[(1-thioxopropyl)amino]butyramido]-3-[[(1,2,4-                         thiadiazol-3-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo-                       [4.2.0]oct-2-ene-2-carboxylic acid                                   19       7-[D-2-phenyl-2-[[(thioxomethyl)amino]acetyl]amino]-                          3-[[(5-butyl-1,2,4-thiadiazol-3-yl)thio]methyl]-8-oxo-                        5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                20       7-[D-2-[[(thioxomethyl)amino]acetyl]amino]-3-[[(1,2,3,                        4-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo-                       [4.2.0]oct-2-ene-2-carboxylic acid                                   21       7-[D-2-cyclohexyl-2-[[(thioxomethyl)amino]acetyl]amino]-                      3-[[(3-methyl-1,2,4-oxadiazol-5-yl)thio]methyl]-8-oxo-                        5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                22       7-[D-2-(1-cyclohexenyl)-2-[[(thioxomethyl)amino]acetyl]-                      amino]-3-[[(1-ethyl-1H-tetrazol-5-yl)thio]methyl]-1-                          azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                         23       7-[D-2-cyclopentyl-2-[[(1-thioxoethyl)amino]acetyl]-                          amino]-3-[[(1-ethyl-1H-tetrazol-5-yl)thio]methyl]-8-                          oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic                          acid                                                                 24       7-[D-2-[(1-thioxopropyl)amino] -2-(2-thienyl)acetyl]-                         amino]-3-[[2-(2-methyl-1,3,4-thiadiazol-5-yl]thio]-                           methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-                          carboxylic acid                                                      25       7-[D-2-[[[(1-thioxoethyl)amino]-2-(1,4-cyclo-                                 hexadien-1-yl)acetyl]amino]-3-[[(5-methyl-1,3,4-                              thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo-                       [4.2.0]oct-2-ene-2-carboxylic acid and potassium                              salt                                                                 26       7-[D-2-[(p-tolyl)-2-[[(thioxomethyl)amino]acetyl]-                            amino]-3-[[(1,3,4-oxadiazol-2-yl)thio]methyl]-8-oxo-                          5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                         and sodium salt                                                      27       7-[D-2-[(2-hydroxyphenyl)-2-(thioxomethyl)amino]acetyl]-                      amino]-3-[[(5-ethyl-1,3,4-oxadiazol-2-yl)thio]methyl]-               8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic                                 acid                                                                 28       7-[D-2-[[(4-aminophenyl)-2-(1-thioxoethyl)amino]acetyl]-                      amino]-3-[[(1,2,3,4-tetrazol-5-yl)thio]methyl]-8-oxo                          5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,                        phenyl ester                                                         29       7-[D-2-(4-ureidophenyl)-2-[[(thioxomethyl)amino]acetyl]-                      amino]-3-[[(1,2,4-thiadiazol-5-yl)thio]methyl]-8-oxo-                         5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,                        triethylamine salt                                                   30       7-[D-2-[4-(methylsulfonylamino)phenyl]-2-[[(thioxo-                           methyl)amino]acetyl]amino]-3-[[(1,2,4-thiadiazol-                             3-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-                        2-ene-2-carboxylic acid pivaloyloxymethyl ester                      31       7-[D-[[2-(2-chlorophenyl)-2-(thioxoethyl)amino]acetyl]-                       amino]-3-[[2-methyl-1,3,4-thiadiazol-5-yl)thio]methyl]-                       8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic                        acid trimethylsilyl ester                                            32       7-[D-2-[[(2-thienyl)-2-(1-thioxoethyl)amino]acetyl]-                          amino]-3-[[(5-methyl-1,2,4-thiadiazol-2-yl)thio]methyl]-                      8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic                        acid, (1-acetyloxy)ethyl ester                                       33       7-[ DL-2-(3-thienyl)-2-[[(thioxomethyl)amino]acetyl]-                         amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-                           8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic                        acid diphenylmethyl ester                                            34       7-[DL-2-phenyl-2-[[(thioxomethyl)amino]acetyl]amino]-                         3-[[1,2,3,4-thiatriazol-5-yl)thio]methyl]-8-oxo-5-                            thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,                          2,2,2-trichloroethyl ester                                           35       7-[DL-2-[[(thioxomethyl)amino]acetyl]amino]-3-                                [[(1,2,3-triazol-5-yl)thio]methyl]-8-oxo-5-thia-1-                            azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                         36       7-[D-2-(1,4-cyclohexadien-1-yl)-2-[[(thioxomethyl)-                           amino]acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)-                          thio]methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-                        2-carboxylic acid, methyl ester                                      37       7-[DL-2-[[(1-thioxoethyl)amino]-2-(2-thienyl]-                                acetyl]amino]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]-                           methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-                          carboxylic acid, benzyl ester                                        38       7-[D-2-phenyl-2-[[(1-thioxoethyl)amino]acetyl]amino]-3-                       [[(1-methyl-1,2,3-triazol-5-yl)thio]methyl]-8-oxo-5-                          thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid                           and potassium salt                                                   __________________________________________________________________________

What is claimed is:
 1. A compound of the formula ##STR18## wherein R ishydrogen, lower alkyl, phenyl-lower alkyl, tri(lower alkyl)silyl,trihaloethyl, ##STR19## alkali metal, alkaline earth metal or (loweralkyl)amine; R₁ is thienyl or phenyl; R₂ and R₅ each is hydrogen orlower alkyl; R₃ is R₆ -thiadiazole, R₆ -oxadiazole, R₆ -triazole,thiatriazole or R₆ -tetrazole; R₄ is lower alkyl, phenyl or phenyl-loweralkyl; and R₆ is hydrogen or lower alkyl.
 2. A compound as in claim 1wherein R₁ is phenyl.
 3. A compound as in claim 1 wherein R₁ is thienyl.4. A compound as in claim 1 wherein R₂ is lower alkyl.
 5. A compound asin claim 1 wherein R₂ is hydrogen.
 6. A compound as in claim 1 whereinR₃ is 1-methyltetrazole.
 7. A compound as in claim 1 wherein R₃ ismethylthiadiazole.
 8. A compound of the formula ##STR20## wherein R ishydrogen, alkali metal, diphenylmethyl or ##STR21## R₁ is phenyl orthienyl; R₂ is hydrogen or methyl; R₃ is (lower alkyl)tetrazole or(lower alkyl)thiadiazole; R₄ is methyl or t-butyl.
 9. A compound as inclaim 1 wherein R and R₂ each is hydrogen, R₁ is phenyl and R₃ is(1-methyl-1H-tetrazol-5-yl).
 10. A compound as in claim 1 wherein R andR₂ each is hydrogen; R₁ is 2-thienyl; and R₃ is1-methyl-1H-tetrazol-5-yl.
 11. A compound as in claim 1 wherein R and R₂each is hydrogen, R₁ is 3-thienyl and R₃ is 1-methyl-1H-tetrazol-5-yl.12. A compound as in claim 1 wherein R and R₂ each is hydrogen, R₁ isphenyl and R₃ is 5-methyl-1,3,4-thiadiazol-2-yl.
 13. A compound as inclaim 1 wherein R is hydrogen, R₁ is 2-thienyl, R₂ is methyl and R₃ is3-methyl-1,2,4-thiadiazol-5-yl.
 14. A compound as in claim 1 wherein Ris alkali metal; R₁ is phenyl, R₂ is hydrogen and R₃ is1-methyl-1H-tetrazol-5-yl.